GROUND DEFORMATION IN A VOLCANIC REGION: A STUDY OF PERIODICITIES

Soufrière Hills Volcano in Montserrat is an active volcano and has been experiencing periods of unrest since a 1995 eruption. We study here the surface deformation associated with the post-eruption period of February 2010 from Global Positioning System data. Geodetic space techniques can be very useful to detect ground deformations, however, seasonal variations present in data should be detected and removed from a time series to prevent bias in any subsequent deformation analysis. In order to clean outliers and identify hidden periodicities within the data, a sliding two-sided-kth neighbour windowing approach and Least Squares Spectral Analysis were applied to the detrended data. Estimated amplitudes of the significant peaks seen during the analysis, and their formal errors, will be presented.